Electronic vaporization apparatuses, including electronic cigarettes, e-cigs, vaporization apparatuses, etc. (referred to herein as “vaporizers” or “vaporizer devices”), have gained popularity in recent years. One reason for the popularity is that vaporizers produce less carcinogens than regular cigarettes and/or other inhalable products when burned and smoked.
Electronic cigarettes are typically battery-powered vaporizers that simulate the feeling of smoking, but without actually burning tobacco. Instead of cigarette smoke, the user inhales an aerosol, commonly called vapor, typically released by a heating element that atomizes a vaporizable material, which may be a liquid solution, a solid, a wax, or a combination of these materials. A user may activate the vaporizer by taking a puff or pressing a button. Some vaporizers look like traditional cigarettes, but they come in many variations.
In many of the electronic cigarettes on the market today, a user-actuated button or user-suction sensor is employed to activate the heating element of the vaporizer. A manual actuation mechanism (e.g. a button, a trigger, or other control that requires a separate user action or input to cause activation of the heating element) for initiating heating may not be desirable in certain situations. For example, requiring use of a button or other manual actuation mechanism may prevent a user from being able to easily synchronize when he or she manually activates the heating and when a puff is taken. Furthermore, if some further user action or input (e.g. a second push of a button, etc.) is required to turn off or otherwise reduce power to the heating element from a vaporization mode, it becomes more likely that the user forgets to cause the heater to turn off, and, as a result, the heater may be left on for a longer period of time than is desirable. Maintaining the heating element at an unnecessarily elevated heating level when airflow is not occurring can lead to scorching of the vaporizable material, as well as a greater level of degradant products in the aerosol to be inhaled. It can also lead to more rapid discharge of a battery or other power source for powering the heating element such that a reduced time between charging may be necessary.
In the case of heating activated by user-caused suction on a vaporizer (e.g. as would be caused by a user “puffing” on the vaporizer or otherwise inhaling to draw air through the vaporizer past the heating element), the heater can be activated when airflow consistent with a user drawing (inhaling into) the mouthpiece of the vaporizer is detected, typically by a pressure sensor or the like. Unfortunately, such user-suction triggered activation is not always reliably implemented due to issues that may arise with commonly used sensors. In at least some vaporizers that utilize user-suction activation of the heating component, a pressure sensor is disposed in communication with the air path. For example, a microphone sensor may be used as the pressure sensor. Such microphone pressure-sensing components are generally quite adaptable for use in vaporizing devices because they tend to be small, very sensitive, and relatively inexpensive. However, they may be less reliable and may break over time. These microphone sensors sense deflection of a fine membrane and output a variance in capacitance. The fine membrane is typically designed to vibrate in the presence of sound and/or pressure waves in the air, and thus will easily deflect under the negative pressure induced by user suction. However, such membranes generally degrade with repeated use and may therefore cause a less reproducible user experience, lose sensitivity to certain puff events, and/or even stop working altogether.
While a microphone-based sensing mechanism can be acceptably functional for controlling heating within a vaporizing device, the longevity of such sensors may be further compromised because they are not designed to function in a vaporizing device environment. Microphone membranes are typically designed to function in a fairly clean and dry environment. In contrast, the environment within or around a vaporizer may be moist, and the membrane may be placed in contact with aerosols, particulates, heat, aqueous and/or non-aqueous liquids, and/or other complicating environmental factors whenever it is in use. Furthermore, over time residue from the vaporized material may deposit onto the membrane. Such residue may saturate the membrane sensor and possibly inhibit membrane deflection altogether, thereby rendering the membrane sensor (and in turn, the heating control of the vaporizing device) inoperable. To mitigate such issues, vaporizer manufacturers have attempted to isolate the microphone from the air path with long and/or circuitous paths. However, these paths can present a design challenge in that they must generally be quite narrow in order to prevent contamination from rapidly reaching the sensor. Unfortunately, the narrow paths can become clogged with viscous material, which can prevent a negative pressure event imparted by a user inhaling or otherwise taking a “puff” on the device from being detected by the microphone. If the material being vaporized is of a low viscosity, it may not prevent the pressure differential from reaching the microphone membrane. However, the fluid may eventually saturate the pressure sensor by capillary action, thereby resulting in reduced or even completely eliminated sensitivity of the sensor.